Ultrasonic wave propagation characteristics can be related to elastic properties of mediums. Hence, the ultrasonic wave has been applied to nondestructive quantitative evaluation of various materials. In the present paper, some examples of the application for composite materials are shown. At first, as a measurement technique of macroscopic elastic properties, a double-through-transmission method is explained. Using this method, changes in elastic constants and viscous coefficients of moisture-induced CFRP were evaluated quantitatively. Next, the measurement of acoustic reflection coefficients with an ultrasonic micro-spectrometer is explained. This is a novel technique for quantitative evaluation of elastic properties in a local area. This technique was applied to the determination of microscopic elastic constants of CMC and a thin resin layer formed in an interlaminar-toughened CFRP composite. Through these examples, the availability of ultrasonic waves is indicated for nondestructive quantitative evaluation of composite materials, which have many unknown elastic constants.